Flow-controlling apparatus



June 1927' c. H. ALLEN FLOW CONTROLLING APPARATUS Original Filed Jan.18. 1922 o mgr 4 Sheets-Sheet 1 W at 3;

21 1927. June c. H. ALLEN FLOW CONTROLLING APPARATUS Originl Filed Jan.l8. 1922 4 Sheets-Sheet 2 1720 mm? Qty $14. 765% 2? I l I t l I l l I l r II un 21 1927. J e c. H. ALLEN FLOW CONTROLLING APPARATUS Original Filed Jan.18. 1922 *4 I O a 5 i=5 1% 0 11mm" 0 2 o P'" as Ex! 4 Sheets-Shet 5 June 21, 1927. I 1,632,780

' 'c. H. ALLEN FLOW CONTROLLING APPARATUS- Original Filed Jan.'l8. 1922 4 Sheets-Sheet 4 QIIIIW I V f? v I In Denim:

an I

Patented June 21, 1927.

rerun COMPANY, or innninocxn'r,

PATENT OFFICE.

CARLTON H. ALLEN, OF DAYTON, OHIO, ASSIGNOB OF ONE-HALF TO GEE LAT N ORTEERN MAINE, A. CORPORATION OF MAINE.

FLOW-CONTROLLING APPARATUS.

Original application filed January 18, 1922, Serial No. 530,140. Divided and this application filed July 17, 1925. Serial No. 44,258.

-This invention relates to apparatus for automatically controlling the flow of steam and will be herein-disclosed as embodied in an apparatus designed especially for use in cooking pulp for paper making.

The usual process of cooking chemical pulp consists in introducing wood in the form of chips into a suitable digester together with the proper chemicals. The digester is then tightly closed and steam is admitted into the bottom of the digester at a-variable rate and for a period of time more or less indefinite. i This addition of heat produces a chemical reaction in the charge of pulp making materials which separates the cellulose from the lignin and other pitchy substances in the wood, and-efi'ects the so-called digesting process. The reaction also results in liberating sulphur dioxid in p considerable quantities, and this gas produces a pressure in the digester which rises to a point in excess of that of the steam at the same temperature. Consequently, in orderto'make room 2,5 for the introduction of more steam, and to keep the digester pressure within practical limits, the pressure is relieved at intervals or continuously by allowing some of the fluids to escape from the digester. The con- 80 ditions within the digester are indicated by.

temperature and pressure recorders, and according to the most approved practice, the

attendant is given detailed instructions as to the temperature and ressure conditions which should be maintained at succeeding intervals of time during the cooking operation. He tries to produce these conditions through the adjustment oi hand valves.

This process, while generally followed in 40 the better pulp mills, is open to the objection that the success of the. process depends to a very great extent on the experience, care and skill of the attendant. So far as conditions existing within the digester are coni 4 corned, the attendant has only the temperature and pressure recorders to guide 'him. Thermometers placed within the digester give only a very rough indication of the conditions therein since the volume of'material within the digester is.very large,.the circulation is sluggish and is constantly changing so that one part of the digester I may be much hotter than another. The variations in pressure in the digester also effeet the steam flowwith a given setting of the steam control valve. Consequently, the lndications which guide the attendant are unreliable. The result of these conditions is a considerable variation in the quality of the pulpv produced by successive cooks, a very irregular rate of "steaming, thus pro; ducing wide fluctuations in the loadon the boilers, and a wide difl'erence in the length of time required to cook individual charges.

It is the chief object of the present invention to devise a reliable and thoroughly satisfactory mechanism for controlling the flow of steam automatically either to a pulp digester or to any other apparatus to which the steam is to be delivered.

The nature of the invention will bereadily understood fromthe following description when read in connection with the accompanying drawings, and the novel features will be particularly pointed outin the appended claims.

Referring now to the drawings,

Figure 1, is a view, somewhat diagrammatic, illustrating a pulp cooking or digesting apparatus embodying theinvention in theform at present preferred;

Fig. 2; is a side elevation of the more important parts of the apparatus that controls the flow of steam to the digester, certain of the parts being shown in cross section; 85

Fig. '3 is a plan view of the apparatus shown in ig. 2;

Fig. 4 is a perspective view. showing certain portions of the apparatus shown in Figs. 2 and 3;- and Fig. 5fis a perspective view of the pawl that actuates the valve operating mechanism, this view showing also the part that is driven by the pawl.

Preliminary to a detailed description of 95 the construction shown in the drawings, it may be stated that. according to the present invention the cooking operation is controlled, not by reference to temperature and pressure conditions existing in the digester, but instead, by predetermining the quantity of heat required tocook a (given charge, and then delivering heat to sai charge at a substantially predetermined "rate until said quantity has been delivered. The quantity 105 of .heat required'to cook a cord, or other i measured quantity of chips, can readily be determined so that it is a matter of simple arithmetic to determine the amount of heat required to cook the charge placed in the digester. In calculating this quantity, the heat losses under the conditions obtaining during the process must also be included.

Referring first to Fig. 1, the construction shown comprises a digester 2, which may be of the usual type, and means for supplying steam to said digester, includin a steam supply line 3, a valve 4 controlling the flow of steam through said line, and an automatic apparatus, which will be described later, for operating saidvalve. The steam supply line delivers steam to the lower end of the digester 2, and a drain pipe 5 also is connected to this end of the digester through a valve 6.

The invention includes a novel apparatus for controlling both the rate of flow of steam to the digester and also the length of time during which said flow shall continue, this apparatus being best shown in Figs. 3 and 4.

Referring to said figures, and particularly to Fig. 2, it will be seen-that the valve 4 comprises a movable valve element or plunger 10 of the balance type, the areas of the opposite ends of this element, however, being so proportioned that the valve has a constant tendency to close when the steam pressure is on it. The valve stem includes a threaded section 12 having a telescoplng connection with another part 13, and these two sections being keyed or splined together so that they are compelled to rotate in unison, but can have 'a relative longitudinal movement. A bevel gear 14 is secured fast on the upper end of the part 13 and meshes with another bevel gear 15 fast on one end of a horizontal shaft 16 which carries a worm gear 17.meshing with a worm' 18 fast 011 a shaft 19, Fig. 3. These shafts, and the parts 12 and 13, are supported in suitable bearings, and the shaft 19 carries a wheel 20 havinga series of pins 21 projecting forward from the face thereof. It is evident that rotation of the pin wheel 20 in. either direction will be transmitted through the mechanism just described to raise or lower the valve-element 10, depending upon the direction of said rotation.

For the purpose of producing this rotative movement of the pin wheel 20, a double actin pawl 22, best shown in Fig. 5, is provide this pawl including oppositely directed dogs 23 and 24, either one of which may be made to engage the pins 21. This pawl has an upwardly extending arm 25 which is connected to the lower end of a crank arm 26, the upper end of this aim being connected to a crank pin or eccentric pm 27 mounted on a disk 28, secured fast on the end of a shaft 30. guide link 31 connected to the joint between the parts 25 and 26 causes the pawl 22 to reciprocate Subbears against one end of a horizontal rod 41 which is supported in suitable guides for longitudinal sliding movement. The weight 40 is sufficient, when it is free to control the pawl 22, to hold this pawl in its right-hand position, Fig. 2, where it will cause a counterclockwise movement of the pin wheel 20, and thus will operate through its connections with the valve element 10 to close this element.

be moved into either a position in which it actuates the connections with the valve 10 to close said valve, or into another position in which it opens said valve, or in an intermediate or neutral position in which it merely reciprocates idly. A. joint control is exerted over this valve operating mechanism by a time mechanism, and by a mechanism which is responsive automatically to changes in the rate of steam flow. In other words, the controlling apparatus includes a mechanism which is driven at a constant speed,

The mounting of the pawl 22 enables it to another mechanism which is automatically responsive to changes in the rate of steam flow, and means for correlating the operations 'of these two mechanisms to cause them to exert a joint control over the valve operating mechanism.

The time element or mechanism just referred to includes the motor 35, a worm 43 fast on the shaft 34'which the motor drives, this worm driving a worm wheel 44 fast on a shaft 45, and carrying an additional worm 46 driving a worm wheel 47 fast on the upper end of a vertical shaft 48. This shaft is threaded for the greater part of its length, as clearly shown in Fig. 2, and carries a nut or follower 50 which engages with the threads of the shaft 48. A controller 51 consisting of a plate of suitable shape, (see Fig. 4), is remova-bly secured to the follower 50 by means of a pin or thumb screw 52 which enables the plate or controller to swing freely relatively to the screw. This controller is so supported that it bears against the left-hand end of the rod 41, previously referred to. A lip or flange 53 projecting from one edge of the part 50 engages wit a stationary part 54 of the frame and prevents the slide 50 from rotating on the shaft 48.

The mechanism responsive to variations in the steam flow comprises a beam 55 fast on a shaft 56, this shaft being machined at opposite sides of the beam to form knife Ilu edgebearings which rest on plates 5757 secured to the machine frame. Two receptacles designated, respectively,at. 58 and 59 are secured fast to the beam, the receptacle 58 being lower and closer to the fulcrum or axis on which the beam tips than the receptacle 59. A pipe 60 connects the lower ends of these two receptacles, and thereceptacle 58 and the pipe connection 60 preferably are substantially filled with mercury, or some. other heavy and relatively non-volatile liquid. A spring 61, connected at one end of the right-hand end of the beam 55 shaped pipe 73, flexi and at its other end adjustably secured to 'the frame by means of. a bolt 62, tends to hold the beam normally in the position in which it is shown in Figs. 2 and 4. The upper ends of the two receptacles or containers 58 and 59 are connected, respectively, to spaced points in the steam conducting pipe or conduits '63, between which points a differential pressure exists that varies with the rate of steam flow. In the present in stance Pitot tubes 64 and 65, respectively,

' Fig 4, are located in the steam pipe 63, the

open end of the tube 64 being directed up stream and that of the tube 65 down stream,

with reference to the direction of steam flow. The tube 64 is connected to the container 58 by means of a pipe 66 leading into a vertical tank 67, a U-shaped pipe 68 leading from the bottom of this tank and connected by a flexible tube69 to piping 70 leading into the top of the container 58. The connections from the Pitot tube 65 to the container 59 are similar to'those just described, and comprise a gipe 71, tank 72, U-

h e tubing 74, and piping 75, all arranged as clearly shown in Fig. 4. The lengths of flexible tubin 69 and 74 are coiled spirally about the s aft 56 so that they exert only a very slight opposition tothe tipping or rocking movement of the beam on its fulcrum, this tipping 45 movement merelywinding up or unwinding slightly the coils 69 and 74. A bracket 76 is secured fast to the shaft 56 and has s aced arms through which adjusting screws'7 and 7 8 are threaded, these screws bearing against the opposite sides 'of an arm 80jmounted loosely on the end portion of the shaft 56. The end of this arm hasan-extension on whleh is mounted a grooved roll, as'shown at 81, Fig. 4, to receive the edge of the controller plate 51, this part of the arm bearing against the controller plate at a point directly opposite the' point of engagement therewith of the rod 41. The differential "pressure between the Pitot tubes 64 and varies with the square of the velocity of the steam flowing throu h the pipe 63. This differential pressure t us is im sed throu h the connections above describe on the b y of mercury 1n the connected receptacles 58 and 59, and tends toforce mercury out of 'nections with the dog- 24 in its workmg position, the opening the receptacle 58 through .thepipe connection 60 and into the receptacle 59. Obviously the quantity of mercury so transferred would depend upon the intensity of the dif ferential pressure between the Pitot tubes and 65. 'The tanks 67 .and 72 and the U-shaped pipe connections 68 and-73 serve to retain a body .of water in the connections and prevent the flow of live" steam into the containers 58 and 59. This apparatus thus is capable of producing a relatively powerful movement of the arm 80. If this arm were mounted to move over a suitable scale, the apparatus would constitute a steam flow meter.

Assuming now that a charge of chips, and other pulp forming materials, has been placed in the digester 2, and that the valves 6 and 10 are both closed, the cooking operation is 'begunby-sw'itching current on to the the double acting pawl or actuator 22 being reciproeated upand down in its neutral or idle position. As soon as the shaft 34 begins to rotate, the slide or follower 50 will begin to rise slowly, being drawn upwardly on the threaded shaft 48. The end 81 of the arm 80 at this time is held'strongly against the edge of the controller plate 51 by the sprmg 61; and as the slide 50 carries the-controller plate slowly upward, the inclined upper surface a of the controller bears against the tip 81 of the arm 80 and tends to swing this arm in a-clockwise direction. The opposite comparatively straight edge I) of the controller bears against the end of the rod 41; and the result of this upward movement of the controller is to slide the rod 41 toward the right, Fig. 2, thus acting through the bell crank lever 38 and rod 37 to move the double acting pawl 22'toward the left, Fig. 2. This inovement renders the dog 24, Fig. 5, operative to act on the pins 21 to rotate the pin wheel 20 step by step in a clockwise direction, and therefore to open the valve element '10. Steam begins to flow through the-con- -from the former into the latter container,

and thereby tipping the beam 55 in a clockwise direction about its fulcrum. This movement swings the end 81 of the ointer or arm 80 away from the edge of the controller plate 51 to an extent determined by the degree of tipping of the beam. If this movement is so small that'the edge I) of the controller 51 still operates through the conpawl 22 totmaintain the movement of the valve will be continued. After a t1me,-however, the flow of steam will be increased to such a point that the end 81 of the arm 80 will be moved far enough so that it will not bear against the edge of the controller plate with sufficient pressure to maintain the pawl 22 in its valve opening position. The weight will then act to move the pawl back to its neutral position where it will simply reciprocate idly without changing the setting of the valve element 10. If the part 81 is moved completely out of contact with the controller plate 51, the weight 40 will swing the pawl 22 toward the right, Fig. 2, far enough to bring the dog 23 into operation on the pin wheel, thus producing a closing movement of the valve plunger 10. This will result in a very short time in swinging the arm 80 back again in a counterclockwise direction and causing the part 81- to bear again against the edge of the controller plate 51 with the results above described. The rate of steam flow thus will depend on the shape of the controller plate 51. Usually a relatively large steam flow is desired during the early stages of the cooking of a charge, and the flow is gradually decreased as the cooking operation progresses. For this reason the plate is made wider at its up er end, as shown, and is gradually decrease in width toward its lower end. The plate is drawn upwardly at a slow but constant rate, and when the end of the plate is withdrawn from between the parts 81 and 41 the flow of steam is automatically shut off, as will readily be,

understood. Usually, however, the steammg 1s stopped by the attendant before this action takes place. The blank space at the upper end of the shaft 48 prevents the slide 50 from rising too far.

The controller plate 51 is removably attached to the slide 50 by a thumb screw 52 so that other plates can be used, as desired, for different batches or'conditions.

In order to facilitate the resetting of the slide 50 after a cook has been completed, it

is split and the two split portions are heldv in operative relationshi to the threaded rod 48 by means of a thum screw 85. By loosening this thumb screw, therefore, the parts are disengaged from the threads of the rod 48 and the slide 50 may be lowered to its orlginal or initial position, as shown in Fig. 2.

An automatic mechanismalso is provided to limit the. maximum adjustment'of the valve plunger 10 that can be madeby the valve operating mechanism.

Referring to Figs. 2 and 3, it will be seen that the shaft 16 has a bevel gear 88 at the inner end thereof meshing with another gear 89 fast on a transverse shaft 90. An arm 91 is fixed to the end of this shaft and is adapted to engage a pin 92 which is secured in an extension 93 ofthepawl 22, as best shown in Fig. 5. Consequently, when the valve operating mechanism has been in operation long enough to cause the arm 91 to make substantially a complete rotation, it will engage the pin 92 and thereby return the pawl 22 to its neutral position. maximum adjustment of the valve plunger 10 in either direction thus is effectually limited.

It willv now be evident that the pulp cooking apparatus above described will operate automatically to deliver steam to the digester at a predetermined but variable rate for a predetermined length of time. This apparatus, therefore, eliminates entirely the uncertain manual control which heretofore has been required, and avoids any necessity for relying on the experience, care, or attention on the part of the attendant. I have demonstrated that a better average quality of pulp is produced by this process, and that the yield of pulp from a given quantity of material is increased. Further more, the sudden and wide fluctuations in steam flow which are produced by the manual control are avoided, thus making it very much easier for the boilers to carry the steam load. An especially important advantage of this process and apparatus is that the average time required to cook a charge is substantially reduced.

By properly designing the controller plate 51, almost any condition encountered in actual practice can be satisfactorily handled. It may also be noted here that this plate forms the connecting link or element between the time mechanism and the mechanism responsive to changes in the rate of steam flow. That is, both of these mechanisms act through this plate to exert a joint control over the action of the valve operating mechanism.

rovided by The flow control apparatus eing more this invention is unique in powerful, and therefore more reliable, than any prior apparatus of this character of which I have been able to learn, and it is contemplated that this apparatus can be used to advantage in controlling the flow offluids other than steam, but which can be handled in the same'general manner. The fact that this mechanism avoids. the necessity for stufiing boxes, with the variable resistance which they offer to the movement of the parts that extend through them, contributes to the reliability and accuracy of this mechanism.

While I have herein shown and described the best embodiment of the invention of' which I am at present aware, it will be appreciated that the invention is susceptible of embodiment in many forms of apparatus differing in details from the construction shown without departing from the spirit or scope of this invention. The present application is a division of my pending app ice.-

The

tion Serial 'No. 530,140, filed January 18,

1922, for improvements in processes and apparatus for cookin pulp, the claims in this case being directe mechanism, while the claims retained in the parent case relate to the pulp cooking apparatus. v

Having thus described my invention, what I desire to claim as newis;

1. An apparatus for controlling the flow of steam, comprising, .in combination, a

of steam, comprising, in combination, a

valve, means for operating said valve, a 'constantly operating mechanism, additional mechanism responsive automatically to the rate of steam flow, and means including a removably mounted controller plate for correlating the operations of. said mechanisms to cause them to exert a joint-mechanical control over the operation of said valve operat: ing means.

3. An apparatus for controlling the flow of steam, comprising, in'combinatiom'a valve,

means for operating said valve, a constantly operating mechanism, additional mechanism responsive automatically to the rate of steamfiow, and means including a. changeable con troller for correlating the operations oi said mechanisms to cause them toex'ert a jointinec hanical control over the operation of said valve operating means. a

4. An apparatus fondbntrolling the flow of steam, comprising, in combination, a valve, means for operating said valve, a constantly operating mechanism, additional mechanism res onsive automaticallv' to the I rate of steam ow, and means including a controller driven. by said constantly operat-' ing mechanism and arranged to be acted upon by said additional mechanism to correlate mechanically the operations of said mechanisms to cause them to exert a joint control over the operation of said valve operating means.

5. An apparatus for controlling the flow of steam, comprisin in combination, a valve for controlling the ow of steam, mechanism for operatin said valve, controlling means for said mec anism including a controlling Y element, constantly acting means for moving said element in one direction, and means dependent wholly u ii the rate of steam direction.

flow for moving sai element in a difierent 6. An apparatus for controlling the flow to the flow controlling- .for controlling the for moving sai controlling ofvsteam,comprisin in combination, a valve moving said element in one direction, and

means responsive to the'rate of steamflow for moving said element in a different direction simultaneously with said movement in the first direction.

7. An apparatus for controlling theflow r of steam, comprisin incombination, a valve ow of. steam, mechanism for operating said valve, controlling means for said mechanism including an arm, a

spring for moving said arm in one direction,

a constantly driven controller for limitin said movement, and means for moving sai armin the opposite direction to an extent dependent upon the rate of steam flow.

8. An apparatus for controlling the flow of steam, comprising, in'combination, a valve for controlling the flow of steam, power driven mechanism for operating said valve, said mechanism including an actuating element operative to cause either an opening or closing movement of the valve, an arm,

mechanism automatically responsive to changes in the rate of steam flow for moving said arm in one direction, a spring for moving the arm in the opposite direction, a con- ,troller against which the, arm strikes when moved in the latter direction, connections for transmitting movement of said controller to said actuatin element, and constantly operating mechanism for moving said controller.

9. An apparatus for controlling the flow of steam, comprising, in combination, a valve, power driven mechanism for operating said valve, said mechanism including an actuating element operative to cause either an opening or closing movement of the valve, an arm, mechanism automatically responsive to chan es in the rate of steam flow arm in one direction, a spring for movin the arm in the opposite direction, a contro ler against which t e arm strikes when moved in the latter direction;

connections for transmitting movement of said controller to said actuating element, a motor, and connections whereby said motor is enabled to move said controller at a constant speed in a direction transversely to the direction of movement of said arm.

10. An apparatus for controlling the flow of steam, comprising, in combination, a valve, mechanism for operatin said valve,

means for said mec anism operated jo' t y I rate of flow of steam, and means for limiting the operation, of said valve by said mechanism.

11. An apparatus for controlling the flow of steam, comprising, in combination a valve, mechanism for operating said valve,

by a time element and by the controlling means for said mechanism operated jointly by a time element and by the rate of flow of steam, and means for automatically interrupting the action of said mechanism when it has made a substantially predetermined adjustment of the valve.

12. An apparatus for controlling the flow of steam, comprising, in combination, a valve, mechanism for operating said valve,

f controlling means for said mechanism operated jointly by a time'element and by the rate of flow of steam, and means for automatically interrupting the action of said mechanism when it has moved the valve to a substantially predetermined extent in either direction.

13. In an apparatus of the character described, the combination of a beam, supporting means therefor constituting a fulcrum on which the beam can tip, connected receptacles supported by said beam at opposite sides of said fulcrum, a body of liquid in said receptacles, a steam conducting conduit, and flexible connections between said receptacles and spaced points in said conduit to subject said body of liquid at opposite sides of said fulcrum to a differential pressure varying with the rate of steam flow, whereby a quantity of said liquid will flow from one side of said fulcrum to the other, the quantity depending upon said rate of steam flow, said connections including flexiible conductors coiled about the axis on which said beam tips.

14. In an apparatus of the character described, the combination of a beam, supporting means therefor constituting a fulcrum, two receptacles supported by said beam, one at each side of said fulcrum, a pipe connecting said receptacles, a body of mercury contained in said receptacles and pipe, a spring tending to hold said beam in a given position, flexible connections leadin from the respective receptacles and coiled about the axis on which said beam tips, a steam conduit, oppositely directed Pitot tubes in said conduit to which said connections lead, respectively, and a device connected with said beam to be operated thereby. I

In testimony whereof I have signed my name to this specification.

CARLTON H. AL] JEN. 

